I can't give you advice on the cab question, but we have been able to do 3 across in the back seat of a Pontiac Vibe by buying narrower car seats. It's a lot cheaper to buy new car seats than a new...

The cheapest place to get sand is in bulk at a quarry, concrete supply place, or landscaping supply (like a place that sells bulk mulch and compost, etc). You do have to have a truck since it's not...